U.S. patent number 7,396,884 [Application Number 10/778,429] was granted by the patent office on 2008-07-08 for hydrogenated nitrile butadiene rubber.
This patent grant is currently assigned to LANXESS Deutschland GmbH. Invention is credited to Dirk Achten.
United States Patent |
7,396,884 |
Achten |
July 8, 2008 |
Hydrogenated nitrile butadiene rubber
Abstract
The present invention relates to a composition containing a
hydrogenated nitrile-butadiene rubber (HNBR), a peroxide
crosslinking system and a resorcinol-formaldehyde resin, to a
process for the preparation of the composition, to the use of the
composition as an adhesion promoter, and also to a multilayer
product containing the composition according to the present
invention.
Inventors: |
Achten; Dirk (Koln,
DE) |
Assignee: |
LANXESS Deutschland GmbH
(Leverkusen, DE)
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Family
ID: |
32731062 |
Appl.
No.: |
10/778,429 |
Filed: |
February 13, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20040166346 A1 |
Aug 26, 2004 |
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Foreign Application Priority Data
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Feb 20, 2003 [DE] |
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103 07 137 |
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Current U.S.
Class: |
525/387; 526/335;
526/341 |
Current CPC
Class: |
C08K
5/14 (20130101); C08L 15/005 (20130101); C08K
5/14 (20130101); C08L 15/005 (20130101); C08L
15/005 (20130101); C08L 61/06 (20130101); Y10T
428/31815 (20150401); C08L 2666/16 (20130101) |
Current International
Class: |
C08C
19/04 (20060101); C08F 8/06 (20060101) |
Field of
Search: |
;525/387
;526/335,341 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 864 607 |
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Sep 1998 |
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EP |
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0 864 607 |
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Sep 1998 |
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EP |
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1 195 403 |
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Apr 2002 |
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EP |
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Other References
Handbuch fur die Gummiindustrie, 2.sup.nd Edition, Jun. 1991, p.
500, published by Bayer AG, "D 10.1 Cohedur". cited by
other.
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Primary Examiner: Choi; Ling-Siu
Attorney, Agent or Firm: Seng; Jennifer R.
Claims
What is claimed is:
1. A composition consisting essentially of a) from 0.1 to 98.4 wt.
% of a HNBR rubber having a nitrile group content of from 10 to 50
wt. % b) from 0.1 to 20 wt. % of a peroxide crosslinking system and
c) from 0.5 to 40 wt. % of a resorcinol-formaldehyde resin, d)
optionally, filler and additives and from 0 to 40 wt. % of metal
acrylates and/or methacrylates.
2. The composition according to claim 1, containing from 20 to 70
wt. % of a HNBR rubber.
3. The composition according to claim 1, containing from 30 to 60
wt. % of a HNBR rubber.
4. The composition according to claim 1, containing from 30 to 15
wt. % of a peroxide crosslinking system.
5. The composition according to claim 1, containing from 3 to 15
wt. % of a resorcinol-formaldehyde resin.
6. Process for the preparation of the composition according claim
1, comprising mixing components a), b) and c).
7. Composite prepared by vulcanizing the composition according to
claim 1 and a carrier material.
8. The composite according to claim 7, wherein the composite is
selected from the group consisting of toothed belts, V-belts,
conveyor belts, coated fabrics, hoses, bags, tires, pneumatic
springs and rubber muscles.
9. Process for the production of a composite comprising vulcanizing
the the composition according to claim 1 with a carrier
material.
10. The process according to claim 9, wherein the carrier material
is selected from the group consisting of polyamide, polyester,
polyaramid, rayon and glass.
Description
FIELD OF THE INVENTION
The present invention relates to a composition containing a
hydrogenated nitrile-butadiene rubber (HNBR), a peroxide
crosslinking system and a resorcinol-formaldehyde resin, to a
process for the preparation of the HNBR composition, to the use of
the HNBR composition as an adhesion promoter, and also to a
multilayer product containing the composition according to the
present invention.
BACKGROUND OF THE INVENTION
There is a great need for compositions which can be used as
adhesive bases for untreated fabrics and reinforcing materials.
Untreated fabrics and reinforcing materials are understood in this
context as being fabrics and reinforcing materials that have not
undergone special surface treatment for adhesion purposes, e.g. by
means of coating processes from solution (impregnation processes)
or using latex dips. The bond between the surface of the carrier
material and the rubber must be sufficiently strong that it does
not constitute the weak point in the composite system.
The direct reaction of the rubber with unpretreated carrier
material and subsequent peroxide crosslinking is not known in the
prior art. Analogous direct adhesion processes are only systems
vulcanizable with sulfur, such as polychloroprene and nitrile
rubber, described in Handbuch fur die Gummiindustrie, 2nd Edition,
1991, p. 500, published by Bayer AG. The use of this process in
peroxide vulcanized systems based on HNBR is not disclosed in the
prior art.
In order to ensure good bonding of the actual rubber that is to be
peroxide crosslinked to the carrier material, the latter must be
pretreated. For the pretreatment, the carrier materials are
treated, for example, with a latex or a solution, for the
application of a so-called finishing layer. Such finishing layers
contain several chemically different constituents. These generally
consist of a rubber selected from the group consisting of
polychloroprene, polyvinylpyridine, polybutadiene or polybutadiene
copolymers, the copolymers being selected from the group consisting
of acrylonitrile, styrene, or mixtures of those polymers.
Furthermore, it is often appropriate to mix with the latex
additional resins, such as resorcinol resins with hardeners such as
formaldehyde (or formaldehyde donors) and optionally silane
compounds. Such latices are referred to as RFL latex
(resorcinol-formaldehyde latex).
The carrier material is immersed in the latex, dried and reacted
fully, and then the actual rubber is vulcanized onto the carrier
material so pretreated. Vulcanization can be carried out both with
sulfur or sulfur systems and peroxide.
The fabrics impregnated with conventional latices based on
polybutadiene or polybutadiene copolymers, polychloroprene or
polyvinylpyridine exhibit distinct weaknesses, particularly after
ageing, when peroxide crosslinked rubbers are used, which are
employed in the next step of manufacture.
In order to improve the ageing properties, EP-B1 0 252 264 and U.S.
Pat. No. 5,176,781 therefore disclose the use of latices based on
partially hydrogenated HNBR and/or in combination with conventional
latices with RFL systems.
For the production of the carrier materials so obtained and
activated for adhesion to peroxide vulcanizable rubber mixtures,
several successive dip cycles or immersion cycles are often
necessary.
Accordingly, the present invention provides a composition which
enables a HNBR rubber to be vulcanized directly onto the carrier
material in question without having to pretreat the reinforcing
material.
SUMMARY OF THE INVENTION
The present invention is directed to a composition containing a)
from 0.1 to 99.4 wt. % of a HNBR rubber, b) from 0.1 to 20 wt. % of
a peroxide crosslinking system and c) from 0.5 to 40 wt. % of a
resorcinol-formaldehyde resin.
DETAILED DESCRIPTION OF THE INVENTION
The HNBR rubber of the composition according to the present
invention can have a nitrile group content of from 10 to 50 wt.
%.
The composition according to the present invention can also contain
further fillers and additives.
The composition according to the present invention can contain, in
addition to the further fillers and additives, also from 0 to 40
wt. % of metal acrylates and/or methacrylates.
The present invention also provides a process for the preparation
of the composition according to the present invention, wherein
components a), b) and c) are mixed.
There is also provided a process for the production of a composite,
wherein the composition according to the present invention is
vulcanized with a carrier material.
In the process for the production of a composite, the carrier
material can be in the form of a fabric or cord selected from the
group consisting of polyamide, polyester, polyaramid, rayon or
glass.
The present invention also provides a composite obtainable by
vulcanization of the composition according to the present invention
and the carrier material.
The composite obtainable by vulcanization of the composition
according to the present invention and the carrier material can be
selected from the group consisting of toothed belts, V-belts,
conveyor belts, hoses, bags, membranes, tires, pneumatic springs
and rubber muscles.
The composition according to the present invention contains from
0.1 to 99.4 wt. % of a HNBR rubber. Preference is given to from 20
to 70 wt. %, more preferably from 30 to 60 wt. %. The expression
HNBR rubber is here to be understood as meaning simple HNBR rubbers
as well as carboxylated HNBR rubbers (HXNBR) and also hydrogenated
HNBR copolymers of butadiene, acrylonitrile and further acrylic or
vinyl monomers. The HNBR rubbers are a highly hydrogenated
nitrile-butadiene or nitrile-butadiene copolymer rubber. Highly
hydrogenated is understood as meaning a content of double bonds in
the HNBR rubber that is less than 40 double bonds per 1000 carbon
atoms, preferably less than 15 per 1000 carbon atoms, more
preferably in the range from 0.2 to 15 double bonds per 1000 carbon
atoms. The HNBR rubber for the composition according to the present
invention preferably has a nitrile group content in the range of
from 10 to 50 wt. %, preferably in the range of from 15 to 39 wt.
%, more preferably in the range of from 20 to 36 wt. %, based on
the total content of the HNBR rubber.
The partial and/or complete hydrogenation of a NBR rubber is
described in DE-A 2 539 132, DE-A 3 329 974, DE 3 056 008, DE-A 3
046 251, EP-A 111 412 and WO-A 01/77185. The HNBR rubber is
prepared in solution, which is later converted into solid
rubber.
The nitrile-butadiene rubber used to produce the HNBR rubber
preferably has a random distribution of the monomer units. Suitable
monomers for the production of the NBR rubber are all unsaturated
monomers known to the person skilled in the art that are
copolymerizable in emulsion with acrylonitrile and butadiene.
Preference is given to copolymers based on acrylonitrile and
butadiene and on acrylonitrile, butadiene, vinyl monomers and
acrylate or methacrylate esters and their free acids.
Preferred unsaturated monomers for the copolymerization include
vinylbenzenes such as styrene, divinylbenzene, methylstyrene,
methacrylonitrile, acrylates such as methyl acrylate, ethyl
acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methacrylates,
such as methyl methacrylate, ethyl methacrylate, butyl
methacrylate, 2-ethylhexyl methacrylate and their free acids,
acrylic acid, methacrylic acid, maleic anhydride, fumaric acid and
itaconic acid.
The composition according to the present invention contains from
0.1 to 20 wt. %, preferably from 3 to 15 wt. %, of a peroxide
crosslinking system. The peroxide crosslinking system contains a
free-radical generator, preferably in combination with an
activator. The proportion of activator in the crosslinking system
as a whole is from 0 to 95 wt. %, preferably from 20 to 70 wt. %.
The proportion of free-radical generator in the crosslinking system
as a whole is in the range from 5 to 100 wt. %, preferably in the
range from 30 to 80 wt. %. There may be used as activators, for
example, triallyl isocyanurate and triallyl cyanurate, di- and
tri-acrylates, cis-1,2-polybutadiene, m-N',N-phenylenedimaleimide
and others. Preference is given to triallyl isocyanurate, triallyl
cyanurate and trimethylol-propane trimethacrylate.
There are used as free-radical generators those compounds whose
10-hour half-life in benzene is over 80.degree. C. Preference is
given to peroxide free-radical generators, such as, for example,
di-tert.-butyl peroxide, di-tert.-butylperoxyiso-propylbenzene,
dibenzoyl peroxide, tert.-butylcumyl peroxide and others.
The composition according to the invention also contains from 0.5
to 40 wt. %, preferably from 3 to 15 wt. %, of a
resorcinol-formaldehyde resin. The resorcinol-formaldehyde resin is
a direct adhesive agent which can be obtained as the condensation
product of phenol derivatives with formaldehyde and/or formaldehyde
donors. Preferred resorcinol-formaldehyde resins include, for
example, products such as Bondingagent R6.RTM. from Uniroyal,
products from the product family Cohedur.RTM. and Vulkadur.RTM.
from Bayer AG. Resorcinol is preferably used as the phenol or
phenol derivative component. Compounds such as
hexamethoxymethylmelamine are frequently used as the formaldehyde
component. The resorcinol-formaldehyde system can be used either in
the form of the individual components (e.g. Cohedur RL.RTM. from
Bayer AG) or in precondensed form (e.g. Vulkadur T). The reactivity
and the adhesion properties can be further influenced by the
addition of suitable catalysts (silica such as e.g. Vulkasil
A1.RTM. (semi-active precipitated aluminum sodium silicate, pH
10-12, surface area 60 m.sup.3/g), Vulkasil N1.RTM. (active
precipitated silica, pH 7, surface area 130 m.sup.3/g) from Bayer
AG). The composition according to the present invention can contain
from 0 to 75 wt. % of further fillers and additives. These are
preferably used in an amount of from 5 to 75 wt. %, more preferably
in an amount of from 30 to 60 wt. %, based on the total composition
of the composition according to the present invention. Fillers and
additives are understood as being any fillers and additives known
to the person skilled in the art which are used in the field of
vulcanized rubber composites and described in Handbuch fur die
Gummiindustrie, 2nd Edition, 1991, published by Bayer AG.
Preference is given to carbon black, silica, inorganic oxides,
stabilizers, plasticizers, processing aids, anti-ageing agents.
From 0 to 40 wt. %, preferably from 5 to 30 wt. %, based on the
total composition of the composition according to the present
invention, of further metal acrylates and/or methacrylates are
preferably added to the composition according to the invention.
Preferred metal (meth)acrylates are zinc diacrylates and zinc
dimethacrylates.
For the preparation of the composition according to the present
invention, components a), b) and c) are mixed together. Apparatuses
known to the person skilled in the art, such as internal mixers and
rollers, are used for the mixing. The preparation of the mixture is
carried out at temperatures known to the person skilled in the art.
A temperature range of from 40 to 140.degree. C. is preferred.
The present invention also provides a process for the production of
a composite from a carrier material and the composition according
to the present invention.
The carrier material is understood as being any fabrics and cords
that are composed of a fiber material. The fiber material is
selected from the group consisting of cotton, rayon, polyamide
fibers such as polycaprolactam, poly(decamethylenecarboxamide)
poly(hexamethyleneadipamide and others), polyaramid fibers
(poly(m)-phenyleneisophthalamide), poly(p)-phenyleneisophthalamide
and others), polyester fibers such as polyethylene terephthalate,
polybutylene terephthalate, poly(cyclohexane 1,4-dimethylene
terephthalate and others, glass fibers, steel cord. Preference is
given to fiber materials composed from the group consisting of
polyamide, polyester, polyaramid, rayon and glass.
For the production of such composites, the composition according to
the present invention is vulcanized with the carrier material at
temperatures in the range of from 120 to 220.degree. C., preferably
from 150 to 200.degree. C., and at a pressure of from 0.5 to 50
bar, preferably in the range of from 2 to 20 bar. The vulcanization
is carried out in presses known to the person skilled in the art,
which determine the shape of the composite that is obtained.
There can be produced a composite selected from the group
consisting of tires, conveyor belts, belts of all kinds, such as
toothed belts, V-belts, reinforced hoses, such as
fire-extinguishing hoses, rubberized fabrics, pneumatic springs and
rubber muscles.
The composites so obtained are distinguished by good adhesion
between the carrier material and the rubber even on ageing. The
resulting composites have good resistance to heat and oil and good
mechanical properties, such as tensile strength and elongation at
break. These composites have the advantage over conventional
composites that they are simple, more rapid and more economical to
produce, because an expensive dipping process for pretreating the
carrier material is unnecessary.
EXAMPLES
Comparison mixtures not in accordance with the invention and
comparison examples resulting therefrom are marked with #.
TABLE-US-00001 TABLE 1 Recipe for different formulations for use as
an adhesive mixture for reinforcing materials. The constituents of
the mixture are given in parts based on the total amount of HNBR
rubber (Therban) used. Constituents of the mixture 1 2 3 4 5 6 7 8#
9# Therban VP KA 8889.sup.1 100 100 -- 10 10 10 10 -- 10 Therban
C3446.sup.2 -- -- 100 90 90 90 90 100 90 Rhenofit DDA-70.sup.3 2 2
2 2 2 2 2 2 2 Corax N 550.sup.4 30 30 30 30 30 30 30 30 30 Cohedur
RL.sup.5 15 15 15 5 10 15 5 -- -- Sartomer SR 633.sup.6 -- -- -- --
-- -- 30 -- -- Struktol ZP1014.sup.7 6 6 -- -- -- -- -- -- --
Aluminum stearate.sup.8 -- 4 -- -- -- -- -- -- -- Stearic
acid.sup.9 -- 1.5 1 -- -- -- -- -- -- PERKADOX 14 40 B-gr.sup.10 --
-- 4 5 5 5 5 5 5
Therban VPKA 8889.sup.1 from Bayer (hydrogenated
acrylonitrile-butadiene-methacrylic acid terpolymer (HXNBR))
Therban C3446.sup.2 from Bayer (hydrogenated
acrylonitrile-butadiene copolymer (HNBR)) Rhenofit DDA-70.sup.3
from Rheinchemie (70% diphenylamine derivative (dry-liquid)) Corax
N 550.sup.4 carbon black, FEF fast extruding furnace from Degussa
Cohedur RL.sup.5 45.5% resorcinol, 45.5% Cohedur A 700, 9% dibutyl
phthalate from Bayer Sartomer Saret S633.sup.6 from Cray, metal
diacrylate with added retarding agent Struktol ZP 1014.sup.7 from
Schill+Seilacher, zinc peroxide approx. 55% dust-free zinc peroxide
provided with dispersant, accelerator for XNBR and HNBR
vulcanization Aluminum stearate.sup.8 from Riedel de Haen AG
Tefacid RG.sup.9 from Tefac (stearic acid) Perkadox 14-40
B-gr.sup.10 DI-(TERT.-BUTYL-PEROXY-ISOPROPYL)-benzene 40% from
Akzo-Nobel
For the preparation of the mixture, the constituents are mixed on a
mixing roller in the following sequence: rubber, carbon black, zinc
diacrylate, stabilizers, peroxide and processing aids. The roller
has a temperature of 60.degree. C.
TABLE-US-00002 TABLE 2 Results of physical tests of the properties
of the mixtures prior to vulcanization Mixture 1 2 3 4 5 6 7 8# 9#
Start of vulcanization 47.6 8.8 >50 >50 >50 >50 >50
>50 - >50 According to DIN 53523 TS 5/120.degree. C.
(min)
TABLE-US-00003 TABLE 3 Results of physical tests of the properties
of the vulcanite's of the composition without reinforcing materials
at room temperature. Vulcanization was carried out at 180.degree.
C. for 20 minutes at 30 bar. Tensile test according Mixture to DIN
53504 1 2 3 4 5 6 7 8# 9# Tensile strength (MPa) 28.8 32 23 23.7
21.9 20.7 27.9 28 27.2 Elongation at break (%) 221 265 517 489 468
461 290 507 519 Modulus at 50% 5.3 5.0 1.4 1.2 1.3 1.4 4.8 1.2 1.2
elongation (MPa) Modulus at 100% 12.1 11 2 1.9 2.1 2.1 10.1 1.8 1.9
elongation (MPa) Modulus at 200% 26.5 26 5.4 5.8 6.5 6.2 21.8 5.6
5.7 elongation (MPa) Modulus at 300% -- -- 10.8 12.2 12.8 12.3 --
12.1 11.9 elongation (MPa) Tear strength according 12.6 13.5 13.2
17.1 11.8 12.7 to DIN 53515 (N) Hardness measurement 82 82 63 60 61
63 84 59 59 (3 .times. 2 mm rod) according to DIN 53505 (Shore
A)
TABLE-US-00004 TABLE 4 Results of the tests of adhesion to various
textile fabrics. The peel strength was determined at 23.degree. C.
according to DIN 53530 at a take-off speed of 100 mm/min. The peel
strengths of mixtures 1 to 9 from a polyamide fabric, from the same
polyamide fabric coated with commercial HNBR-RFL latex and from a
rayon fabric were tested on the peel test specimens described in
DIN 53530. The specimens were vulcanized at 180.degree. C. for 30
minutes at 30 bar. Mixture 1 2 3 4 5 6 7 8# 9# Peel strength N/25
mm N/10 mm Polyamide fabric 157* 220* 384* 125* 126* 110* 61** 8**
5** Untreated Polyamide fabric 13.4** 17.8** 94** coated with RFL-
HNBR Rayon fabric 43** 49** 50** 25** 25** 26** Untreated *breakage
of the rubber **breakage at the point of transition between the
fabric and the mixture
Although the invention has been described in detail in the
foregoing for the purpose of illustration, it is to be understood
that such detail is solely for that purpose and that variations can
be made therein by those skilled in the art without departing from
the spirit and scope of the invention except as it may be limited
by the claims.
* * * * *